Women, their Offspring and iMproving lifestyle for Better cardiovascular health of Both.

The WOMB project is a follow-up study of the Lifestyle study that was set up to investigate the costs and effects of a structured lifestyle program in overweight and obese subfertile couples to prevent unnecessary treatment and improve reproductive outcome. Both women and their offspring will be part of the WOMB follow-up study.

This part only contains study information about the children born to women in the Lifestyle study (WOMB kids). Click for more information about WOMB women or go to the WOMB website or the website of the Lifestyle study.

RationaleThe WOMB kids project is designed to determine whether a preconception lifestyle intervention or preconception weight loss has a fetal programming effect. The WOMB kids project presents a unique opportunity to capitalize on the randomized controlled trial (RCT) design of the Lifestyle study as genetic variability and parental characteristics should, like other ‘unknown’ factors, be balanced between the two study groups. In WOMB kids, potential fetal programming effects will be examined independent of short-term outcomes, and will be measured by examining postnatal growth, health, development and lifestyle.

ObjectiveTo investigate the effect of a preconception lifestyle program (aimed at weight loss of 5-10% of the original body weight) for overweight and obese subfertile women on the growth, health, development and lifestyle of the child.

Study designProspective follow up cohort study of children born to participants of the Lifestyle study, a multicenter randomized clinical trial. The WOMB kids project includes the initial follow-up by questionnaires. Thereafter, parents will be asked to participate with their children in a further follow-up by a clinical visit.

Study populationThe study population comprises all singleton children born to couples participating in the Lifestyle study. These couples were subfertile, and women had a BMI of at least 29. The women were randomly allocated to a six-month structured lifestyle program preceding conventional fertility care or to immediate conventional fertility care. Both groups were followed up until 24 months after randomization. Children conceived within this 24 months follow-up period are included.

MethodsObservational study of children born to women who participated in the Lifestyle study.

Outcome measuresThe primary outcome measure is the child’s BMI at 3-5 years. Secondary outcome measures are: 1) child’s health between 0 and 3-5 years, 2) child’s growth pattern between 0 and 3-5 years, 3) child’s development and behavior at 3-5 years, 4) child’s lifestyle (diet, physical activity, and sleep pattern) at 3-5 years.

Power/data analysisIn the Lifestyle study, 157 singletons were born in the control group, and 144 singletons in the intervention group. For the WOMB Kids, we estimate that approximately 80% of children of women in the study will be followed to 3-5 year of age (or known to have died before this age). Thus, we expect to study 126 children from the control group and 115 children from the intervention group This will give us 82% power to detect a 0.5 difference in BMI (15.3 kg/m2 versus 15.8 kg/m2 with SD 1.3 (as from literature on BMI of 4/5 year olds) between the two groups.

Time scheduleStart recruitment: spring 2015Planned duration of the study: 4 years